The world's oldest digital computers

By By AUBREY COHEN

on November 26, 2012 2:49 PM

Photo: Keystone/Getty Images

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Last week, 61 years after it was built and three years after restoration began at The National Museum of Computing, in Bletchley Park, England, the Harwell Dekatron became the world's oldest working digital computer. The nearly 2.8-ton machine uses 828 flashing Dekatron valves, 480 relays and a bank of paper. It works in decimal, unlike most computers, which are binary. Click on for a video and more photos of this and other early
computers. less

Last week, 61 years after it was built and three years after restoration began at The National Museum of Computing, in Bletchley Park, England, the Harwell Dekatron became the world's oldest working digital ... more

Photo: The National Museum Of Computing

Last week, 61 years after it was built and three years after... Photo-3796453.52982 - Connecticut Post

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The Harwell Dekatron computer, which first ran in 1951, is shown during its original life. It first ran at Harwell Atomic Energy Research Establishment, slowly,
but relentlessly and flawlessly carrying out tedious calculations. The
computer subsequently went to Wolverhampton and Staffordshire Technical
College, which renamed it the WITCH (Wolverhampton Instrument for
Teaching Computation from Harwell) and used it in computer education
until 1973. After a period on display in the former Birmingham Museum of
Science and Industry, it was dismantled and put into storage.
Volunteers from The National Museum of Computing rediscovered it in
2008. less

The Harwell Dekatron computer, which first ran in 1951, is shown during its original life. It first ran at Harwell Atomic Energy Research Establishment, slowly,
but relentlessly and flawlessly carrying out ... more

Photo: The National Museum Of Computing

The Harwell Dekatron computer, which first ran in 1951, is shown... Photo-3796455.52982 - Connecticut Post

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A detail of the Harwell Dekatron computer, which first ran in 1951, is shown restored in the U.K. National Museum of Computing. It is the world's oldest working digital computer.

A detail of the Harwell Dekatron computer, which first ran in 1951, is shown restored in the U.K. National Museum of Computing. It is the world's oldest working digital computer.

Photo: The National Museum Of Computing

A detail of the Harwell Dekatron computer, which first ran in 1951,... Photo-3796454.52982 - Connecticut Post

Image 4 of 34

A detail of the Harwell Dekatron computer, which first ran in 1951, is shown restored in the U.K. National Museum of Computing. It is the world's oldest working digital computer.

A detail of the Harwell Dekatron computer, which first ran in 1951, is shown restored in the U.K. National Museum of Computing. It is the world's oldest working digital computer.

Photo: The National Museum Of Computing

A detail of the Harwell Dekatron computer, which first ran in 1951,... Photo-3796452.52982 - Connecticut Post

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Item-12971.52982 - Connecticut Post

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The Colossus computer is shown in its original life. It was the world's first modern computer, assembled in 1943 and up and running in January 1944. It was built to help decipher the encrypted messages between German Chancellor Adolph Hitler and his generals during World War II. less

The Colossus computer is shown in its original life. It was the world's first modern computer, assembled in 1943 and up and running in January 1944. It was built to help decipher the encrypted messages between ... more

Photo: The National Museum Of Computing

The Colossus computer is shown in its original life. It was the... Photo-3796450.52982 - Connecticut Post

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The Colossus computer is shown restored in the U.K. National Museum of Computing. It was the world's first modern computer, assembled in 1943 and up and running in January 1944. It was built to help decipher the encrypted messages between German Chancellor Adolph Hitler and his generals during World War II. less

The Colossus computer is shown restored in the U.K. National Museum of Computing. It was the world's first modern computer, assembled in 1943 and up and running in January 1944. It was built to help decipher ... more

Photo: The National Museum Of Computing

The Colossus computer is shown restored in the U.K. National Museum... Photo-3796451.52982 - Connecticut Post

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The Hollerith tabulator and sorter box, invented by Herman Hollerith and used in the 1890 United States census, is shown in this photo circa 1960. This precursor to modern digital computers 'read' cards by passing them through electrical contacts. Closed circuits, which indicated hole positions, could then be selected and counted. Hollerith's Tabulating Machine Company, founded in 1896, was a predecessor to International Business Machines (IBM). less

The Hollerith tabulator and sorter box, invented by Herman Hollerith and used in the 1890 United States census, is shown in this photo circa 1960. This precursor to modern digital computers 'read' cards by ... more

A man checks the installation of the Elliott 402 'Electric Brain' at the British Instrument Industries Exhibition on June 27, 1955 at Earl's Court, London. The original caption for this photo boasted: "This electronic computer can solve complicated mathematical problems in one hour." less

A man checks the installation of the Elliott 402 'Electric Brain' at the British Instrument Industries Exhibition on June 27, 1955 at Earl's Court, London. The original caption for this photo boasted: "This ... more

H A Thomas, manager of the Instrumentation and Control section of Unilever's engineering department, gives the Faraday lecture on January 26, 1959 at London's Festival Hall. His subject is 'Automation' and here he demonstrates the workings of an electronic calculator or computer. less

H A Thomas, manager of the Instrumentation and Control section of Unilever's engineering department, gives the Faraday lecture on January 26, 1959 at London's Festival Hall. His subject is 'Automation' and ... more

Photo: Jimmy Sime, Getty Images

H A Thomas, manager of the Instrumentation and Control section of... Photo-3796280.52982 - Connecticut Post

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A National-Elliot 803 computer is loaded onto a customized Austin 32 cwt van on June 4, 1960 at the Boreham Wood factory of Elliott-Automation, in England. It was bound for the British Scientific Instrument Manufacturers Association Exhibition in Moscow at the request of the Soviet government, which stipulated delivery was to be made by road. The Elliott 803 was a fully transistorized digital electronic computer. less

A National-Elliot 803 computer is loaded onto a customized Austin 32 cwt van on June 4, 1960 at the Boreham Wood factory of Elliott-Automation, in England. It was bound for the British Scientific Instrument ... more